Amyotrophic lateral sclerosis is regarded generally as a disease of the upper and lower motor neurons. The clinicoanatomic description of the disorder, which was first made by Charcot1 in 1865, was later confirmed by other observers. The gross atrophy of the motor convolutions was observed by Kahler and Pick2 in 1879. Kojewnikoff3 was the first to trace the degeneration of the pyramidal fibers from the motor cortex into the internal capsule, peduncles, pons, medulla oblongata and spinal cord. Charcot and Marie,4 who confirmed Kojewnikoff's3 observations, also demonstrated the disappearance of the giant pyramidal cells from the motor cortex. These changes were not always constant, and in 1 instance Marie5 was unable to detect them. Sarbó,6 Rossi and Roussy,7 Probst,8 Campbell9 and Spiller,10 in further contributions, stressed the involvement of area 4; Rossi and Roussy,7 Probst8 and Campbell